1. Field of the Invention
The invention relates to a direct current voltage supply apparatus. Particularly, the invention relates to a direct current voltage supply apparatus capable of cutting off a direct current (DC) power supply when a DC voltage is unstable.
2. Description of Related Art
Generally, a power supply is used to supply an operating voltage for a server system. The current power supply generally receives an alternating current (AC) voltage of 100V-230V first, and a transformer inside the power supply transforms the AC voltage into a direct current (DC) voltage (for example, 12V) to serve as the operating voltage of the server system. In this case, protection measures of the 12V DC voltage are all built in the power supply.
However, in view of a developing trend, the operating voltage of the server system is no longer provided by the AC voltage, but is directly provided by the DC voltage (for example, 12V) supplied by an end client. In this case, the server system cannot use the power supply, and the power supply is replaced by a DC board. However, the DC board is still required to have all of the protection measures (i.e. over voltage protection (OVP) and under voltage protection (UVP)) as that of the power supply. Therefore, how to achieve the OVP and the UVP of the DC board as that of the power supply is an important issue to be researched and developed.